1. Field of the Invention
The present invention relates generally to circuit testing devices. More specifically, the present invention is directed to a device for testing circuit continuity in firing circuits or electrically initiated pyrotechnic devices.
Prior to igniting an explosive or pyrotechnic device, it is customary to check the circuit in order to insure that at the desired time the device will operate.
When working with explosive and/or pyrotechnic devices, testing devices must meet safety standards which insure that accidental ignition of explosive devices incorporated in the circuit or device does not occur.
Further, such testing devices are preferably quick and easy to utilize and will operate in a variety of environmental conditions.
2. Brief Description of the Prior Art
Known devices for testing circuit continuity are typically meters of various types. In other words, a meter is used to check, for example, the current or resistance of a circuit. If the meter provides feedback from the test, as a direct by-product of the information, there is a confirmation that the circuit is complete. If the meter is unable to produce a reading, the tester assumes that the circuit is broken at some point.
For example, a galvanometer is a device known for testing circuits. Generally, the galvanometer is an instrument for detecting and measuring the strength of an electric current. Galvanometers depend on the fact that force is generated by an electric current flowing in a magnetic field. One example of a galvanometer comprises a magnetic needle suspended in a wire coil. As current passes through the coil, the needle is deflected. The deflection is proportionate to the current, therefore by measuring the deflection on a calibrated scale the current may be determined. The deflection may be measured by an optical system, e.g. reflection of a beam of light from a small mirror attached to the needle and observation of the reflection beam on a scale. The galvanometer may have a fixed coil and a movable magnet or vice versa.
Only as a logical conclusion from the measurement of the current does one know that the circuit is complete.
The known devices are relatively large and complex and require a variety of moving parts. Further, they are susceptible to failure due to environmental conditions and component breakdown. Still further, as known devices typically have several moving parts for measurements, they generally require more power and/or current flow.